This invention relates generally to the method and apparatus for the electrostatic transfer of the developed image from a master to a receiving surface. More specifically, it pertains to the registration of the master and the master transport assembly with the receiving surface to achieve accuracy of the transferred image and repeatability of the process.
In industrial processes utilizing the transfer of a desired image from a master to a receiving surface, there is a need to have a functional system which ensures the accurate transfer of the image from the master to the receiving surface. The transfer process must be repeatable, so that the transferred image is transferred to the same location on each receiving surface. The degree of precision can vary whether the application for the transfer from the master to the receiving surface is color printing, photographic printing, film strip printing, or printed circuit printing onto flexible or rigid receiving surfaces. Although the manufacturer of printed circuits can require more precise transfer because of the increasing density and finer lines and line-spacings being employed, the registration system must be accurate for all applications.
Where the registration system is employed in graphic arts applications transferring multiple colors, successes and treatments to the same receiving surface to obtain a 2, 3, or 4 color copy, the registration system must provide an accurate and repeatable transfer. Similarly, where printed circuits are to be produced, the increasing use of two side circuit boards requires that the images be aligned on both sides of the boards to precise tolerances.
Previous registration systems have employed the use of registration pins to engage perforations in a receiving flexible web, transfer prerecorded information from one roller wound flexible web to a second roller round flexible web with preprinted information already thereon by controlling the velocities of the two webs, utilized a rigid table with a transparency thereon to repeatedly position the transparency over a receiving location through the use of horizontally acting solenoid pins, and a pin alignment system with floating pins for use in the photographic printing to allow the pins to float in holes on the pin board on which serves as a flat support for a mask/film sandwich.
None of the prior systems have required the precise tranfer of the image from a master to a receiving surface where the master is carried on a flexible web that is kept in tension. Prior systems fail to minimize the number of dimensions and fits that must be actually held in order to produce the final result with the fine tolerances apparently required.
These problems are solved in the method and design of the present apparatus and permits a master transport assembly to be precisely aligned with a stationary receiving surface to achieve accurate and reapeatable image transfer.